Google's SPDY networking protocol is designed to dramatically improve page load times and integrate additional security into the web browsing experience. Support for the latest and greatest version of the protocol should ensure Firefox 27 stays as close as possible to the cutting edge.

Transport layer security is a crucial part of keeping the web safe, and Firefox 27 now supports the latest versions of the TLS protocol by default. Versions 1.1 and 1.2, introduced in 2006 and 2008, respectively, are the most up-to-date variants of the TLS layer.

Mozilla has fixed four critical security flaws in Firefox 27. One involved a JavaScript flaw that caused potentially exploitable crashes, while two others involved incorrect handling of certain types of images from websites, leading to a use-after-free and another type of potentially exploitable crash. Finally, various memory safety hazards were also corrected.

A range of other potential security vulnerabilities were also fixed in Firefox 27, including XSLT stylesheet issues, and problems with handling of JavaScript access to Windows objects and NSS tickets. Another fix ended a problem where certain types of applications could be exploited to read the Android system log on some older versions of that operating system.